Automatic parachute ground release



J 1952 M. HATTAN AUTOMATIC PARACHUTE GROUND RELEASE Filed Sept. 11, 1947 INVENTOR.

Patented Jan. 22, 1952 UNITED STATES PATENT OFFICE AUTOMATIG- PARACHUTE GROUND RELEASE (Granted under the act of March 3, .1883, as amended April 30, 1928; 3 70 0. G. 75 7) 10 Claims.

fluids which. may freeze or leak; requires no static line to'the airplaneand which stays with the-parachute.

Another object is to provide a device which has an adjustabletime delay to prevent opening during anyxno-load condition following the opening shock.

Referring to. the accompanying drawings,

Fig; 1 is a side elevation of'the device with load connections, but with no load applied.

Fig. 2 is a side: elevation of a fragment comprising the lower half of: Fig. 1, the load connectionsindicatingthe application of load.

:Fig. 3 is a side elevation corresponding toFig. 1,.showing the load connections ejected fromthe device.

Fig. Me a front elevation of the deviceby. itself.

Fig. 5 is a longitudinal section taken onthe line 5550f Fig. 4.

Fig. .6 is a sectional detail taken on the line Ger-30f Fig. 4.

In: Figs. -1 and 3, are the shroudlines ex.- tending to the parachute canopyv (not shown) H issa canopyv link, of which thethere are two (the second-not beingshownxeach link II extending through an opening I2 in .a' hook l3. In the shank of hook l3 there is an ofiset l5 which serves-to center the load vertically. It is also shown in Fig. 5. Below the ofiset l5 the shank l3 terminates in a bight 16, the inner surface .ll of which slopes toward the shank l3, and thereby formsa reversed parabolic curve. The curved surface I 1 is-adapted to compel aload-supporting link such as [3, when in contact with surface I! and under load, to move sideways on surface I] towardshank M into the bight of the parabola.

The time-delay device comprises a dashpot chamber casting 2l which is attached to the shank I 4 both above and below the offset portion l5. In it is bored-a vertical cylindrical-opening 22, in which fits closely, a freepiston 123. The latter has;a clearance of about 0,001 5" on each side which should be such that it takes the piston 23 about seven seconds to fall out of the opening 22' when unhindered. For special purposes, the-clearance may be varied to make the rate of fall any desired one, but seven seconds is preferred] The piston may be graduated so that when inserted to less than its full length, lesser periods of tall are brought about. The piston 23 is somewhat longer than the opening 22.

Just below the lower end of casting 2| there is a widened portion 24 cfthe shank l4 (Fig.4). Through it extend two slidable rods 2-5. The rods 25 at their right-hand or rear ends are connected by a yoke, the inner surface of which is curved to fit the outerend of the piston 23, which projects a short distance out of dashpot casting 21 when inserted as -far as it will go. Between the rods 25 there is a coil spring 27, one end of which is retained in a shallow opening 29 in the-shank l4 and the other end in a link ejector 28 by a channel 30 therein- Spring 2'! is normally compressed when the device is in the position shown in Figs. 1, 2 and 5, but retains considerable compression when in the .positionshown in Fig. 3. In other words, it is arather strong spring; strongenough to eject a load supporting link-from thebight it, but weak enough'to be compressed by the movement of theloaded'link sinking into the lowest portion of the bight. The ejector 28 is-mounted on those ends of the rods 25whioh are within the bight l6. Ejector 28 also serves as a retaining device forthe link l9as long as the piston 23 is in'the dashpot opening 22 and the link I9 is unloadedv The operation pf the deviceis as follows:

With the piston 23 absent, the yoke 26 is pressed toward the shank .l 5, bringing the ejector 28 to theposition shown in Fig. 3; The load link I9 is slipped into a channel 3| in the ejector-'28, piston 23 inserted and the pressure is released. Link i9 assumes theposition shownin Fig. l; the piston 23 having'beenmeanwhile inserted. Yoke 26 is'now pressing. against the piston 23, thereby preventing it from falling. out.

Nowassuming that the parachute and the-load, connected by my device, are launched together. The load exerts a pull on link l9, pulling the latter into-the bight of the curved surface I'I. Sidewise force is transmitted through ejector28 and ro o r ss s ri 2 thereby releas n yoke/26 from contact with piston 23. The latter now begins to fall slowly out of opening or chamber 22. If ano-load conditionshould occur during that time, yoke 26 would again contact the iston Hand-Inflati of i k 19 would c u When the load reaches ground however, a noload condition will occur, if the piston has been set correctly, after the piston has fallen out. A correct setting of the piston is to insert it into opening 22 so far that it will not fall out before the no-load condition due to parachute opening shock occurs, but that it will have fallen out before the load reaches the earth. The setting of the piston in the chamber 22 is therefore chosen with regard to the altitude from which the load and parachute are launched and other considerations such as the diameter of canopy in relation to the weight and air resistance of the load.

The no-load condition at landing causes the spring 21 to expand, which it can do because the link I9 is no longer pulled into the bight of surface I'I. The ejector 28 therefore suddenly assumes the position shown in Fig. 3 and link I9 is thrown clear of surface [1. cannot drag the load, even though the canopy should be blown along the surface of the ground.

The piston 23 may be flexibly attached by a chain to the yoke 26 to make it recoverable although such attachment is not regarded as part of my invention. The piston may also hear indicia showing the length of time that will be taken to fall from various lengths of insertion.

I claim as my invention:

1. In an automatic parachute release device,

a hook having a shank, a dashpot attached to the rear of said shank, time delay means comprising a free piston in said dashpot, means for retaining a load-supporting link in the bight of said hook while the piston remains in the dashpot under a loadless condition, said retaining means comprising a yoke adapted to contact said piston substantially while the latter remains in the dashpot, rods extending transversely through said shank over said bight, an ejector member adapted to fit over a load carrying link and a coil spring concentric with said rods between said ejector and said shank, the length of said rods and the strength of said spring being so chosen that the spring can be compressed sufiiciently when a normal load is attached to the load-carrying link to free the piston from contact with the yoke due to the movement of the ejector as it follows the link into the lowest portion of the bight by reason of load stress exerted on the load-carrying link and strong enough to eject said link from the bight substantially as soon as a no-load condition occurs by reason of the load making contact with the ground.

2. In an automatic parachute release device a hook having a bight, a flattened shank and eyes for the attachment of a canopy, an ejecting device mounted through the shank of the hook and being movable over the bight thereof at such distance from the inner surface thereof as to provide room for a load supporting link and being normally spring pressed along said bight and finally beyond said bight when the hook is unloaded, a dashpot attached to that surface of the shank which faces away from the bight, a free piston in said dashpot and projecting therefrom, a retaining yoke for said piston on said ejection device for retaining said piston in the dashpot under no-load conditions, spring means on said ejection device of a strength suitable to urge said retaining yoke against the projecting end of said piston when the hook is in no-load condition and to free said piston to fall when the hook is loaded and to traverse said ejection device beyond the bight of said hook at no-load condi- The canopy then tion if such condition occurs after said piston has dropped free.

3. In an automatic parachute ground release, a shanked hook for attaching the canopy and suspending the load, an ejector for ejecting a load-supporting link outwardly along the bight of said hook and finally free from said hook, said ejector comprising a channeled block slidable across the bight of said hook, a compressed coil spring capable of storing sufficient energy for ejection of the link under no-load condition of said link, said spring being retained between said block and the face of said hook, slidable rods supporting at one end thereof said block and extending through said hook at the shank portion thereof, a yoke attached to the ends of said slidable rods at the other end, a dashpot casting attached to that face of the shank away from which the bight of the hook extends, a free piston in said dashpot casting, said piston extending beyond said casting sufficiently to be in contact with and retained by said yoke and spring when there is no load upon said hook and free of said piston when the hook is loaded said freedom occurring by reason of further compression of said spring due to movement of said ejector over the bight toward said shank due to a load-supporting link occupying the channel of said ejector sinking into the bight of said hook toward the shank thereof.

4. In an automatic parachute release device of the class in which a load retaining ring is retained in the bight of a hook under load and ejected therefrom at no load, a time-delay device attached to said hook vertically on the shank thereof, said time-delay device comprising a dashpot, a close-fitting piston in said dashpot normally projecting therefrom at the lower end thereof, a channeled block extending over the bight of the hook, said channel being adapted to retain a load-supporting link between said bight and said block, slidable rod means extending through the shank and supporting said block on one end and on the other a piston restraining yoke, said yoke being adapted to contact said piston at noload condition the restraint of said piston being made inoperative by a movement of said channeled block and said link into the bight of said hook under the gravitational urge of the loaded load-supporting link to occupy the lowest position in the bight of said hook whereby to release said yoke from contact with said piston and permit the piston to fall free, and normally-compressed spring means having sufficient potential energy for moving said channeled block beyond the hook upon the occurrence of a no-load condition on the load-supporting link after the fall of said piston, whereby to eject said link from the bight of said hook.

5. In an automatic parachute release device a hook having eyes, a bight and a flat shank, a combined load link retaining and ejection member comprising a channeled block, slidable rods positioned by their ends in said block and pressing said shank, a yoke joining said rods on that side of the shank that is opposite to said block, a dashpot attached to the same side of said shank a close fitting piston in said dashpot positioned to fall away therefrom if unrestrained and projecting from the dashpot when fully inserted therein, a coil spring normally urging said block, and its attached rods beyond the bight of said hook whereby to restrain said piston by contact with said yoke, said spring being of such strength that it may be compressed by the action of a loaded load supporting link in the bight of said hook to move the block inward on the bight toward the lowest point thereof and thereby free the piston from contact with said yoke and allow said piston to fall, and after the complete freedom of said piston from said dashpot to eject a load link free of said book by moving said block and link over the bight and then free of said hook when a no-load condition occurs on said link.

6. A device according to claim 5 in which the shank of the hook is offset to center the load.

*7. An automatically releasable parachute load comprising, a hook member including an upper shank portion rigidly connected to a lower hook portion, means at the upper end of said shank portion to connect said hook member to a parachute, said hook portion providing an upwardly opening recessed bight portion to receive a loadcarrying link normally depending from said hook portion, a link ejector member mounted on said shank portion for movement transversely thereof and including a link engaging portion between the upper end of said link and said shank portion when said link occupies said bight portion, spring means acting to bias said link ejector in a direction to move said link-engaging portion away from said shank portion, said spring means having a horizontal component weak enough to allow the link to sink into the bight portion while under load, but strong enough to eject the load-carrying link from said bight portion when the load is removed from said link, whereby said link ejector acts to eject said link from said bight portion when the parachute supported load attached to said link reaches the ground and said load is no longer effective to hold said link in said bight portion against the force of the spring biased link ejector.

8. An automatically releasable parachute load connector comprising, a hook member including an upper shank portion rigidly connected to a lower hook portion, means at the upper end of said shank portion to connect said hook member to a parachute, said hook portion providing an upwardly opening recessed bight portion to receive a load-carrying link normally depending from said hook portion, a link ejector member mounted on said shank portion for movement transversely thereof and including a link engaging portion between the upper end of said link and said shank portion when said link occupies said bight portion, spring means acting to bias said link ejector in a direction to move said linkengaging portion away from said shank portion, said spring means having a horizontal component weak enough to allow the link to sink into the bight portion while under load, but strong enough to eject the load-carrying link from said bight portion when the load is removed from said link, means providing a dashpot cylinder on said shank portion opening downwardly, a free piston in said cylinder blocking the potential sidewise movement of said link ejector member and ceasing to block the link ejector upon the latter bein forced sidewise under the influence of the loadcarrying link sinking into the bight portion, whereupon said piston drops out of said cylinder, whereby the free piston drops from said cylinder by force of gravity during the free fall of a loaded parachute and whereby said link ejector acts to eject said link from said bight portion when the parachute supported load attached to said link reaches the ground and said load is no longer effective to hold said link in said bight portion against the force of the spring biased link ejector.

9. In an automatic parachute release device, a hook having a shank, a dashpot attached to the rear of said shank, a free piston in said dash pot, means for restraining said piston during a noload condition and for retaining a load supporting link by the weight of the load in the bight or said hook when said link is under load, spring means for moving said retaining and restraining devices and link outwardly along the bight of the hook and then free from the hook when the load supporting link becomes unloaded, said spring means having a horizontal component weak enough to allow the link to sink into the eight portion while under load, but strong enough to eject the load-carrying link from said bight portion when the load is removed from said link, said restraining means comprising a yoke, a rod supporting said yoke at its outer end, an ejector supported by said rod at its inner end over said load-supporting link, said rod passing through the shank of said hook and supporting said retaining device, said spring means being mounted about said rod, said yoke being releasable from contact with said piston by the action of the load in moving said restraining means toward the lowest point on the bight of said hook whereupon said piston is free to fall under the action of gravity.

10. In an automatic parachute ground release, a hook for suspending a load, means for retaining a load suspending member within the bight of said hook by the weight of the load upon said member, spring means for ejecting said load suspending member outwardly along the bight of said hook when a no-load condition occurs and finally free of said hook said spring means having a horizontal component weak enough to allow the link to sink into the bight portion while under load, but strong enough to eject the load-carrying link from said bight portion when the load is removed from said link, time delay means carried at the rear of the shank of said hook, a yoke carried to the outer end of said spring means in contact with said time delay means during a noload condition, said retaining means being positioned over the bight of said hook and actuable thereover so that when the load suspending member is drawn to the lowest point of the bight of said hook by the application of the load thereto, said yoke is released from contact with said time delay means, the operation of said spring means being inhibited by said time delay means until the loss of said time delay means unlocks said spring means.

MARK HATTAN.

REFERENCES CITED UNITED STATES PATENTS Name Date Maskey June 24, 1947 Number 

